add a note to automatic retry (#21927)

[ti-chi-bot]

This is an automated cherry-pick of #21927

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• v8.5 (TiDB 8.5 versions)
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What is the related PR or file link(s)?

• This PR is translated from:Fix outdated statement about TiDB's default transaction mode in optimistic-transaction.md docs-cn#21007
• Other reference link(s):Fix outdated statement about TiDB's default transaction mode in optimistic-transaction.md #21921

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[gemini-code-assist]

Summary of Changes

Hello @ti-chi-bot, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request updates the documentation for optimistic transactions in TiDB, specifically focusing on the automatic retry mechanism. The changes aim to provide clearer and more up-to-date information regarding when automatic retries are disabled or unsupported, and the implications for transaction isolation. This ensures users have accurate guidance on handling transaction conflicts and understanding TiDB's behavior across different versions.

Highlights

• Documentation Clarification: Added a prominent note to the 'Automatic retry' section of the optimistic transaction documentation, detailing changes in retry behavior across TiDB versions.
• Transaction Retry Behavior: The new note clarifies that automatic transaction retry is disabled by default from TiDB v3.0.0 due to potential transaction isolation level breaches, and that automatic retries for optimistic transactions are no longer supported from TiDB v8.0.0.
• Content Refinement: Removed a sentence that previously mentioned TiDB providing an internal retry mechanism to lower application adaptation difficulty, streamlining the text to reflect current retry policies.

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[gemini-code-assist]

Code Review

This pull request adds a note about the automatic retry feature in optimistic transactions. The change is helpful, but it introduces a contradiction with the surrounding text. I've provided a suggestion to rephrase the section for better clarity and technical accuracy, ensuring that the documentation correctly reflects that the feature is deprecated in recent versions.

[hfxsd]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hfxsd

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